Jari Korpi

User studies in cartography : opportunities for empirical research on interactive maps and visualizations

ABSTRACT The possibility of digital interactivity requires us to reenvision the map reader as the map user, and to address the perceptual, cognitive, cultural, and practical considerations that influence the user’s experience with interactive maps and visualizations. In this article, we present an agenda for empirical research on this user and the interactive designs he or she employs. The research agenda is a result of a multi-stage discussion among international scholars facilitated by the International Cartographic Association that included an early round of position papers and two subsequent workshops to narrow into pressing themes and important research opportunities. The focus of our discussion is epistemological and reflects the wide interdisciplinary influences on user studies in cartography. The opportunities are presented as imperatives that cross basic research and user-centered design studies, and identify practical impediments to empirical research, emerging interdisciplinary recommendations to improve user studies, and key research needs specific to the study of interactive maps and visualizations.

The prospects for urban densification: a place-based study

Study of the environmental outcomes of urban densification is a highly context-dependent task. Our study shows that collecting and processing place-based survey data by means of the softGIS method is clearly helpful here. With the map-based internet questionnaire each response remains connected to both the physical environment and the everyday life of the respondent. In our study of the Kuninkaankolmio area (located in the Helsinki metropolitan region) the survey data were combined with urban density variables calculated from register-based data on the existing built environment. The regression analysis indicated that the participants in the survey preferred the same density factors for their future residence as they enjoyed in their current neighbourhood. In the second analysis we related the densities of planned infill developments with the interest respondents had shown in these projects. The results show that new and even quite dense infill developments have been found to be rather attractive, with them often being viewed as interesting supplements to the current urban texture. These findings contribute to the ongoing scientific discussion on the feasibility of densification measures and encourage the Kuninkaankolmio planners to proceed, albeit carefully, with the planned infill developments.

Clutter Reduction Methods for Point Symbols in Map Mashups

Abstract Map mashups are often visually chaotic and methods for solving this chaos are required. We introduce a set of clutter reduction criteria for evaluating methods to reduce clutter in map mashups. We present a synthesis of cartographic generalisation operators for point data and clutter reduction methods used in information visualisation and evaluate the methods against the criteria. The resulting evaluation table can be used in finding suitable clutter reduction methods for cases of map mashups with different primary criteria, and more specifically in finding methods that cover each others’ limitations.

Cultural Constraints in the Design of Pictographic Symbols

Abstract title/> International crisis management is a field where numerous national, organisational and domain cultures encounter one another, causing problems in information transfer between various actors. The symbols used in situation maps in this kind of an environment should be culturally independent and value-free in order to be properly understood. However, designing culturally independent symbols is difficult because the cultural background of an individual is complex and influences the interpretation of symbols in many ways. In this paper, we discuss the influences of different cultural background factors on both the design and the comprehension of map symbols. Cultural influences are considered as conventions in code systems, definitions in formal and informal conceptual models, and conventions in aesthetic judgments. As examples in the discussion, we use findings from a symbol design project for situation maps in international crisis management.

Identification of partially occluded map symbols

Maps should be legible at all scales, and the information density of a map should be adapted to fulfill this goal. However, there are situations in which overlapping symbols might not be easily avoided. These kinds of cluttered or over-plotted situations often occur today in geovisual analytics and in map mash-ups created using Web 2.0 technologies. In this research project, we examine via a user test the extent to which occluded symbols can still be identifiable. Specifically, we tested how different levels of occlusion affected the accuracy and response time of finding symbols that varied in either color hue, abstract shape, or pictogram. The results of the test show that the efficiency of the symbols decreases when the symbols become partially occluded. Still, even half-occluded complex shapes can be identified quite accurately. Symbols varying in color hue seem to tolerate occlusion the best.

Experiencing bivariate colour scales on animated maps

ABSTRACT We examined animated maps on which two different datasets are presented together in order to test the applicability of the bivariate colour scales to moving phenomena. Experimental software, combining meteorological datasets, was implemented to study two different use cases: the comparison between a predicted model and the actual observations of a single phenomenon, and the causality between two independent phenomena. The characteristics of different datasets and tasks were taken into account when designing the visualizations for these two combinations. These visualizations were then evaluated in group interviews. The results from the interviews indicate that designing the colours for animated bivariate maps differs remarkably from the colours of static bivariate maps, and the applicability of previous bivariate data visualization guidelines can be questioned. The spatial coverage, geometrical complexity and movement of the phenomena have a significant effect on bivariate animations.

Effect of Cultural Differences and Referent Characteristics on the Design of Pictographic Map Symbols

Pictographic symbols are used on many kinds of maps because they are able to convey information efficiently. There is still little research on the factors that affect the comprehension of map symbols. In this paper, we analyze the semantic contents of map symbols designed by university students from different countries to study how (1) the concepts to be depicted and (2) the differences in the cultural backgrounds of designers affect the design of the symbols. The results suggest that cultural conventions strongly affect the design and interpretation of map symbols. For some concepts, it is difficult to design an intuitive symbol, even for a user group with a homogeneous cultural background, because of the broadness of the concept or the lack of a logical representation strategy for the concept. In practice, easily interpretable symbols can be achieved by involving a representative set of intended users in creating ideas for the symbols.

An experimental analysis of three methods for highlighting colorful pictographic symbols

Highlighting is one of the key functionalities of any interactive visualization environment. Yet, there is little research on highlighting methods. This article focuses on highlighting of colorful pictographic symbols. Three strategies for highlighting were tested by implementing three highlighting methods that were suggested suitable in the literature on attention, perceptual grouping, and motion detection. An experimental design measuring response times and accuracy was used and subjective opinions were collected. The three available strategies for applying the highlighting effect to a subset of visually salient (i.e., colorful) symbols are: (1) to decrease the saliency of the non-highlighted symbols, (2) to increase the saliency of the highlighted symbols, and (3) to add a connecting element for grouping the highlighted symbols. Of these strategies, adding a connecting element was found to be the least efficient based on the response times, whereas both methods for tuning the saliency difference between the highlighted and non-highlighted symbols were found to be equally efficient. However, decreasing the saliency of the non-highlighted symbols was clearly preferred in the subjective evaluation.